Affiliations: [a]
University of Memphis, Memphis, TN, USA
| [b]
University of Nevada Las Vegas, Las Vegas, NV, USA
Correspondence:
[*]
Address for correspondence: Robert Townsend, MS, P.O. Box 381093, Germantown, TN 38183, USA. Tel.: +1 901 484 5247; Fax: +1 901 328 6382; E-mail: [email protected].
Abstract: BACKGROUND: Distraction based material handling tests are used to measure effort during functional capacity evaluations. OBJECTIVE: To identify validity of effort using the under loading method with the XRTS Lever Arm. Classification of effort between the two sessions (100% effort and estimated 50% effort) was compared with current validity criteria. METHODS: Fifty healthy and asymptomatic subjects were tested under two conditions (100% effort and an estimated 50% effort). Comparisons were made between percent changes from crate lifts to lever arm lifts from three starting heights (0.25 m, 0.38 m and 0.051 m). RESULTS: During the 100% effort sessions, no subject had a mean percent change >20%, a majority of lift comparison >25% or a single lift comparison >30%. The specificity of the current validity criteria is 100%. The under loading method of using the XRTS lever arm was 20% sensitive in identifying an equivocal or invalid test result when subjects gave an estimated 50% effort. CONCLUSIONS: The results indicate the under loading method of distraction based testing is very specific but lacks sensitivity in identifying feigned weakness with asymptomatic, non-injured individuals. The high specificity of the test should eliminate concern of having a false positive for insincere effort during functional testing.
